This application claims the priority of German patent document 199 37 151.2, filed Aug. 6, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to an active occupant restraint system for a motor vehicle, having a central control unit and a plurality of active restraining devices and associated triggering units that are connected by way of an ignition bus line system for transmitting ignition information to the central control unit, the ignition bus line system comprising at least one ring line and/or at least one stub line.
In an occupant restraint system of this generic type, such as disclosed, for example, in German Patent Document DE 196 19 117 A1, the end stages of a triggering electronic system for an active occupant restraint system in a motor vehicle are connected to a central control unit by lines which are configured in a stub shape and in a ring shape.
German Patent Document DE 198 13 963 A1 discloses another active occupant restraint system for a motor vehicle which comprises a central control unit with ignition bus lines configured in a ring shape and in a stub shape. Control modules for active occupant protection systems are embedded in the ignition bus lines. The active occupant protection systems include belt tightening devices for drivers, front passengers and rear occupants, as well as rear, side, window and knee air bags in the driver, front passenger and rear passenger area. They are combined into groups having the same method of operation, spatial correlationship and/or common triggering in the event of a certain accident type with a respective pertaining ring or stub line. Thus, the rear and knee air bags for drivers or front passengers are triggered by way of a first ignition bus line arranged in a ring shape. All belt tightening devices in the motor vehicle are situated in a second ring configured ignition bus line; side and window air bags for the driver and front passenger are ignited by means of stub-configured ignition bus lines. The control modules assigned to the active occupant restraint systems are arranged in the ignition bus lines corresponding to their triggering sequence in the event of a crash. Those active occupant restraint systems which, in the event of a crash, are triggered earlier than others are situated farther away from the central control unit in the line paths than are the control modules of active occupant restraint systems which ignite later when triggered.
The article by M. Bischoff, "Networked Restraint Systems", Automobil-Produktion, Jun. 1997, describes a bus line system with a central control unit, in which ignition end stages for a plurality of active occupant protection systems in a motor vehicle are connected with the central control unit via a tree structure. The ignition end stages are combined in groups corresponding to the function of the active occupant protection systems to which they are assigned. Thus, for example, the ignition end stages of the active occupant protection systems for side impact and for frontal impact are situated on different lines. As a result, even in the event of a side impact, which can result in a destruction of the bus line to the ignition end stages of the active occupant protection systems for a side impact, it is still possible to trigger the active occupant protection systems which protect against a frontal impact, because these are controlled in a different bus line branch.
It is an object of the invention to provide an active occupant restraint system of the initially mentioned type with a high reliability
This and other objects and advantages are achieved by the active occupant restraint system according to the invention, in which the triggering units are arranged within respective ring lines and/or stub lines of the ignition bus line system as a function of a definable protection significance priority of the retraining devices assigned to the triggering units. In particular the triggering units are situated farther away from the central control unit with a decreasing protection significance priority.
One embodiment of the invention comprises one or more multi-stage restraining devices with pertaining triggering units, in which the triggering unit pertaining to a higher stage of each multi-stage restraining device is situated in the corresponding ring or stub line, closer to the central control unit than the triggering unit pertaining to a lower stage.
In this manner, a modular active occupant restraint system is created in which the same modules can be used, and which is particularly suitable when using only one or a few variants of triggering units for the flexible installation into different vehicle types. Further, such an occupant restraint system requires only a comparatively small number of line paths in the vehicle for controlling the triggering units. In particular, the ignition bus principle with only a few line channels permits the use of peripheral units which are connected to the bus line system by means of plugs which have only a few connection pins.
In a further embodiment of the invention, the triggering units of active restraining devices that are activated at different times are arranged as a function of the triggering sequence of the restraining devices assigned to the triggering units, such that the triggering unit of a restraining device with an earlier triggering time is farther away from the central control unit than that of a restraining device with a later triggering time. In this manner, even when some of the triggering units are already ignited (so that the ignition bus line in the area of these triggering units may be damaged), it can be ensured that ignition commands can always reach the triggering units which are arranged on the output side and are not ignited, via the bus system.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.